#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iomanip>
#include <stack>
#include <queue>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <fstream>
#include <chrono>
#include <random>
#include <bitset>
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) ((int)(x).size())
#define pb push_back
#define mod 1000000007
using ll = long long;
using namespace std;
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}


int main(){
  int N; cin >> N;
  vector<int> W(N); rep(i,N) cin >> W[i];
  int sum = 0;
  rep(i,N) sum += W[i];
  if(sum%2==1) {
    cout << "impossible" << endl;
    return 0;
  }
  else{
    vector<vector<bool>> dp(N+1,vector<bool>(sum+1,false));
    dp[0][0] = true;
    for(int i=1; i<=N; i++){
      int w = W[i-1];
      rep(j,sum){
        if(dp[i-1][j]) dp[i][j] = true;
        if(dp[i-1][j] && j+w<=sum){
          dp[i][j+w] = true;
        }
      }
    }

    rep(i,N+1){
      if(dp[i][sum/2]){
        cout << "possible" << endl;
        return 0;
      }
    }
  }
  cout << "impossible" << endl;
  return 0;
}